resolv/ns_print.c

   1 /*
   2  * Copyright (c) 1996-1999 by Internet Software Consortium.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
   9  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15  * SOFTWARE.
  16  */
  17
  18 #if !defined(_LIBC) && !defined(lint)
  19 static const char rcsid[] = "$BINDId: ns_print.c,v 8.18 2000/02/29 05:48:12 vixie Exp $";
  20 #endif
  21
  22 /* Import. */
  23
  24 #include <sys/types.h>
  25 #include <sys/socket.h>
  26
  27 #include <netinet/in.h>
  28 #include <arpa/nameser.h>
  29 #include <arpa/inet.h>
  30
  31 #include <assert.h>
  32 #include <errno.h>
  33 #include <resolv.h>
  34 #include <string.h>
  35 #include <ctype.h>
  36
  37 #ifdef SPRINTF_CHAR
  38 # define SPRINTF(x) strlen(sprintf/**/x)
  39 #else
  40 # define SPRINTF(x) ((size_t)sprintf x)
  41 #endif
  42
  43 /* Forward. */
  44
  45 static size_t   prune_origin(const char *name, const char *origin);
  46 static int      charstr(const u_char *rdata, const u_char *edata,
  47                         char **buf, size_t *buflen);
  48 static int      addname(const u_char *msg, size_t msglen,
  49                         const u_char **p, const char *origin,
  50                         char **buf, size_t *buflen);
  51 static void     addlen(size_t len, char **buf, size_t *buflen);
  52 static int      addstr(const char *src, size_t len,
  53                        char **buf, size_t *buflen);
  54 static int      addtab(size_t len, size_t target, int spaced,
  55                        char **buf, size_t *buflen);
  56
  57 /* Proto. */
  58
  59 #ifndef _LIBC
  60 u_int16_t       dst_s_dns_key_id(const u_char *, const int);
  61 #endif
  62
  63 /* Macros. */
  64
  65 #define T(x) \
  66         do { \
  67                 if ((x) < 0) \
  68                         return (-1); \
  69         } while (0)
  70
  71 /* Public. */
  72
  73 /*
  74  * int
  75  * ns_sprintrr(handle, rr, name_ctx, origin, buf, buflen)
  76  *      Convert an RR to presentation format.
  77  * return:
  78  *      Number of characters written to buf, or -1 (check errno).
  79  */
  80 int
  81 ns_sprintrr(const ns_msg *handle, const ns_rr *rr,
  82             const char *name_ctx, const char *origin,
  83             char *buf, size_t buflen)
  84 {
  85         int n;
  86
  87         n = ns_sprintrrf(ns_msg_base(*handle), ns_msg_size(*handle),
  88                          ns_rr_name(*rr), ns_rr_class(*rr), ns_rr_type(*rr),
  89                          ns_rr_ttl(*rr), ns_rr_rdata(*rr), ns_rr_rdlen(*rr),
  90                          name_ctx, origin, buf, buflen);
  91         return (n);
  92 }
  93
  94 /*
  95  * int
  96  * ns_sprintrrf(msg, msglen, name, class, type, ttl, rdata, rdlen,
  97  *             name_ctx, origin, buf, buflen)
  98  *      Convert the fields of an RR into presentation format.
  99  * return:
 100  *      Number of characters written to buf, or -1 (check errno).
 101  */
 102 int
 103 ns_sprintrrf(const u_char *msg, size_t msglen,
 104             const char *name, ns_class class, ns_type type,
 105             u_long ttl, const u_char *rdata, size_t rdlen,
 106             const char *name_ctx, const char *origin,
 107             char *buf, size_t buflen)
 108 {
 109         const char *obuf = buf;
 110         const u_char *edata = rdata + rdlen;
 111         int spaced = 0;
 112
 113         const char *comment;
 114         char tmp[100];
 115         char errbuf[40];
 116         int len, x;
 117
 118         /*
 119          * Owner.
 120          */
 121         if (name_ctx != NULL && ns_samename(name_ctx, name) == 1) {
 122                 T(addstr("\t\t\t", 3, &buf, &buflen));
 123         } else {
 124                 len = prune_origin(name, origin);
 125                 if (len == 0) {
 126                         T(addstr("@\t\t\t", 4, &buf, &buflen));
 127                 } else {
 128                         T(addstr(name, len, &buf, &buflen));
 129                         /* Origin not used or not root, and no trailing dot? */
 130                         if (((origin == NULL || origin[0] == '\0') ||
 131                             (origin[0] != '.' && origin[1] != '\0' &&
 132                             name[len] == '\0')) && name[len - 1] != '.') {
 133                                 T(addstr(".", 1, &buf, &buflen));
 134                                 len++;
 135                         }
 136                         T(spaced = addtab(len, 24, spaced, &buf, &buflen));
 137                 }
 138         }
 139
 140         /*
 141          * TTL, Class, Type.
 142          */
 143         T(x = ns_format_ttl(ttl, buf, buflen));
 144         addlen(x, &buf, &buflen);
 145         len = SPRINTF((tmp, " %s %s", p_class(class), p_type(type)));
 146         T(addstr(tmp, len, &buf, &buflen));
 147         T(spaced = addtab(x + len, 16, spaced, &buf, &buflen));
 148
 149         /*
 150          * RData.
 151          */
 152         switch (type) {
 153         case ns_t_a:
 154                 if (rdlen != NS_INADDRSZ)
 155                         goto formerr;
 156                 (void) inet_ntop(AF_INET, rdata, buf, buflen);
 157                 addlen(strlen(buf), &buf, &buflen);
 158                 break;
 159
 160         case ns_t_cname:
 161         case ns_t_mb:
 162         case ns_t_mg:
 163         case ns_t_mr:
 164         case ns_t_ns:
 165         case ns_t_ptr:
 166                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 167                 break;
 168
 169         case ns_t_hinfo:
 170         case ns_t_isdn:
 171                 /* First word. */
 172                 T(len = charstr(rdata, edata, &buf, &buflen));
 173                 if (len == 0)
 174                         goto formerr;
 175                 rdata += len;
 176                 T(addstr(" ", 1, &buf, &buflen));
 177
 178
 179                 /* Second word, optional in ISDN records. */
 180                 if (type == ns_t_isdn && rdata == edata)
 181                         break;
 182
 183                 T(len = charstr(rdata, edata, &buf, &buflen));
 184                 if (len == 0)
 185                         goto formerr;
 186                 rdata += len;
 187                 break;
 188
 189         case ns_t_soa: {
 190                 u_long t;
 191
 192                 /* Server name. */
 193                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 194                 T(addstr(" ", 1, &buf, &buflen));
 195
 196                 /* Administrator name. */
 197                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 198                 T(addstr(" (\n", 3, &buf, &buflen));
 199                 spaced = 0;
 200
 201                 if ((edata - rdata) != 5*NS_INT32SZ)
 202                         goto formerr;
 203
 204                 /* Serial number. */
 205                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 206                 T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
 207                 len = SPRINTF((tmp, "%lu", t));
 208                 T(addstr(tmp, len, &buf, &buflen));
 209                 T(spaced = addtab(len, 16, spaced, &buf, &buflen));
 210                 T(addstr("; serial\n", 9, &buf, &buflen));
 211                 spaced = 0;
 212
 213                 /* Refresh interval. */
 214                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 215                 T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
 216                 T(len = ns_format_ttl(t, buf, buflen));
 217                 addlen(len, &buf, &buflen);
 218                 T(spaced = addtab(len, 16, spaced, &buf, &buflen));
 219                 T(addstr("; refresh\n", 10, &buf, &buflen));
 220                 spaced = 0;
 221
 222                 /* Retry interval. */
 223                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 224                 T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
 225                 T(len = ns_format_ttl(t, buf, buflen));
 226                 addlen(len, &buf, &buflen);
 227                 T(spaced = addtab(len, 16, spaced, &buf, &buflen));
 228                 T(addstr("; retry\n", 8, &buf, &buflen));
 229                 spaced = 0;
 230
 231                 /* Expiry. */
 232                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 233                 T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
 234                 T(len = ns_format_ttl(t, buf, buflen));
 235                 addlen(len, &buf, &buflen);
 236                 T(spaced = addtab(len, 16, spaced, &buf, &buflen));
 237                 T(addstr("; expiry\n", 9, &buf, &buflen));
 238                 spaced = 0;
 239
 240                 /* Minimum TTL. */
 241                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 242                 T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
 243                 T(len = ns_format_ttl(t, buf, buflen));
 244                 addlen(len, &buf, &buflen);
 245                 T(addstr(" )", 2, &buf, &buflen));
 246                 T(spaced = addtab(len, 16, spaced, &buf, &buflen));
 247                 T(addstr("; minimum\n", 10, &buf, &buflen));
 248
 249                 break;
 250             }
 251
 252         case ns_t_mx:
 253         case ns_t_afsdb:
 254         case ns_t_rt: {
 255                 u_int t;
 256
 257                 if (rdlen < NS_INT16SZ)
 258                         goto formerr;
 259
 260                 /* Priority. */
 261                 t = ns_get16(rdata);
 262                 rdata += NS_INT16SZ;
 263                 len = SPRINTF((tmp, "%u ", t));
 264                 T(addstr(tmp, len, &buf, &buflen));
 265
 266                 /* Target. */
 267                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 268
 269                 break;
 270             }
 271
 272         case ns_t_px: {
 273                 u_int t;
 274
 275                 if (rdlen < NS_INT16SZ)
 276                         goto formerr;
 277
 278                 /* Priority. */
 279                 t = ns_get16(rdata);
 280                 rdata += NS_INT16SZ;
 281                 len = SPRINTF((tmp, "%u ", t));
 282                 T(addstr(tmp, len, &buf, &buflen));
 283
 284                 /* Name1. */
 285                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 286                 T(addstr(" ", 1, &buf, &buflen));
 287
 288                 /* Name2. */
 289                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 290
 291                 break;
 292             }
 293
 294         case ns_t_x25:
 295                 T(len = charstr(rdata, edata, &buf, &buflen));
 296                 if (len == 0)
 297                         goto formerr;
 298                 rdata += len;
 299                 break;
 300
 301         case ns_t_txt:
 302                 while (rdata < edata) {
 303                         T(len = charstr(rdata, edata, &buf, &buflen));
 304                         if (len == 0)
 305                                 goto formerr;
 306                         rdata += len;
 307                         if (rdata < edata)
 308                                 T(addstr(" ", 1, &buf, &buflen));
 309                 }
 310                 break;
 311
 312         case ns_t_nsap: {
 313                 /* 2*255 for hex digits, 128 for '.' and '\0', 2 for
 314                    0x if inet_nsap_ntoa starts using it.  */
 315                 char t[255*2 + 128 + 2];
 316
 317                 (void) inet_nsap_ntoa(rdlen, rdata, t);
 318                 T(addstr(t, strlen(t), &buf, &buflen));
 319                 break;
 320             }
 321
 322         case ns_t_aaaa:
 323                 if (rdlen != NS_IN6ADDRSZ)
 324                         goto formerr;
 325                 (void) inet_ntop(AF_INET6, rdata, buf, buflen);
 326                 addlen(strlen(buf), &buf, &buflen);
 327                 break;
 328
 329         case ns_t_loc: {
 330                 char t[255];
 331
 332                 /* XXX protocol format checking? */
 333                 (void) loc_ntoa(rdata, t);
 334                 T(addstr(t, strlen(t), &buf, &buflen));
 335                 break;
 336             }
 337
 338         case ns_t_naptr: {
 339                 u_int order, preference;
 340                 char t[50];
 341
 342                 if (rdlen < 2*NS_INT16SZ)
 343                         goto formerr;
 344
 345                 /* Order, Precedence. */
 346                 order = ns_get16(rdata);        rdata += NS_INT16SZ;
 347                 preference = ns_get16(rdata);   rdata += NS_INT16SZ;
 348                 len = SPRINTF((t, "%u %u ", order, preference));
 349                 T(addstr(t, len, &buf, &buflen));
 350
 351                 /* Flags. */
 352                 T(len = charstr(rdata, edata, &buf, &buflen));
 353                 if (len == 0)
 354                         goto formerr;
 355                 rdata += len;
 356                 T(addstr(" ", 1, &buf, &buflen));
 357
 358                 /* Service. */
 359                 T(len = charstr(rdata, edata, &buf, &buflen));
 360                 if (len == 0)
 361                         goto formerr;
 362                 rdata += len;
 363                 T(addstr(" ", 1, &buf, &buflen));
 364
 365                 /* Regexp. */
 366                 T(len = charstr(rdata, edata, &buf, &buflen));
 367                 if (len < 0)
 368                         return (-1);
 369                 if (len == 0)
 370                         goto formerr;
 371                 rdata += len;
 372                 T(addstr(" ", 1, &buf, &buflen));
 373
 374                 /* Server. */
 375                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 376                 break;
 377             }
 378
 379         case ns_t_srv: {
 380                 u_int priority, weight, port;
 381                 char t[50];
 382
 383                 if (rdlen < NS_INT16SZ*3)
 384                         goto formerr;
 385
 386                 /* Priority, Weight, Port. */
 387                 priority = ns_get16(rdata);  rdata += NS_INT16SZ;
 388                 weight   = ns_get16(rdata);  rdata += NS_INT16SZ;
 389                 port     = ns_get16(rdata);  rdata += NS_INT16SZ;
 390                 len = SPRINTF((t, "%u %u %u ", priority, weight, port));
 391                 T(addstr(t, len, &buf, &buflen));
 392
 393                 /* Server. */
 394                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 395                 break;
 396             }
 397
 398         case ns_t_minfo:
 399         case ns_t_rp:
 400                 /* Name1. */
 401                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 402                 T(addstr(" ", 1, &buf, &buflen));
 403
 404                 /* Name2. */
 405                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 406
 407                 break;
 408
 409         case ns_t_wks: {
 410                 int n, lcnt;
 411
 412                 if (rdlen < NS_INT32SZ + 1)
 413                         goto formerr;
 414
 415                 /* Address. */
 416                 (void) inet_ntop(AF_INET, rdata, buf, buflen);
 417                 addlen(strlen(buf), &buf, &buflen);
 418                 rdata += NS_INADDRSZ;
 419
 420                 /* Protocol. */
 421                 len = SPRINTF((tmp, " %u ( ", *rdata));
 422                 T(addstr(tmp, len, &buf, &buflen));
 423                 rdata += NS_INT8SZ;
 424
 425                 /* Bit map. */
 426                 n = 0;
 427                 lcnt = 0;
 428                 while (rdata < edata) {
 429                         u_int c = *rdata++;
 430                         do {
 431                                 if (c & 0200) {
 432                                         if (lcnt == 0) {
 433                                                 T(addstr("\n\t\t\t\t", 5,
 434                                                          &buf, &buflen));
 435                                                 lcnt = 10;
 436                                                 spaced = 0;
 437                                         }
 438                                         len = SPRINTF((tmp, "%d ", n));
 439                                         T(addstr(tmp, len, &buf, &buflen));
 440                                         lcnt--;
 441                                 }
 442                                 c <<= 1;
 443                         } while (++n & 07);
 444                 }
 445                 T(addstr(")", 1, &buf, &buflen));
 446
 447                 break;
 448             }
 449
 450         case ns_t_key: {
 451 #ifndef _LIBC
 452                 char base64_key[NS_MD5RSA_MAX_BASE64];
 453                 u_int keyflags, protocol, algorithm, key_id;
 454                 const char *leader;
 455                 int n;
 456
 457                 if (rdlen < NS_INT16SZ + NS_INT8SZ + NS_INT8SZ)
 458                         goto formerr;
 459
 460                 /* Key flags, Protocol, Algorithm. */
 461                 key_id = dst_s_dns_key_id(rdata, edata-rdata);
 462                 keyflags = ns_get16(rdata);  rdata += NS_INT16SZ;
 463                 protocol = *rdata++;
 464                 algorithm = *rdata++;
 465                 len = SPRINTF((tmp, "0x%04x %u %u",
 466                                keyflags, protocol, algorithm));
 467                 T(addstr(tmp, len, &buf, &buflen));
 468
 469                 /* Public key data. */
 470                 len = b64_ntop(rdata, edata - rdata,
 471                                base64_key, sizeof base64_key);
 472                 if (len < 0)
 473                         goto formerr;
 474                 if (len > 15) {
 475                         T(addstr(" (", 2, &buf, &buflen));
 476                         leader = "\n\t\t";
 477                         spaced = 0;
 478                 } else
 479                         leader = " ";
 480                 for (n = 0; n < len; n += 48) {
 481                         T(addstr(leader, strlen(leader), &buf, &buflen));
 482                         T(addstr(base64_key + n, MIN(len - n, 48),
 483                                  &buf, &buflen));
 484                 }
 485                 if (len > 15)
 486                         T(addstr(" )", 2, &buf, &buflen));
 487                 n = SPRINTF((tmp, " ; key_tag= %u", key_id));
 488                 T(addstr(tmp, n, &buf, &buflen));
 489 #endif /* !_LIBC */
 490
 491                 break;
 492             }
 493
 494         case ns_t_sig: {
 495 #ifndef _LIBC
 496                 char base64_key[NS_MD5RSA_MAX_BASE64];
 497                 u_int type, algorithm, labels, footprint;
 498                 const char *leader;
 499                 u_long t;
 500                 int n;
 501
 502                 if (rdlen < 22)
 503                         goto formerr;
 504
 505                 /* Type covered, Algorithm, Label count, Original TTL. */
 506                 type = ns_get16(rdata);  rdata += NS_INT16SZ;
 507                 algorithm = *rdata++;
 508                 labels = *rdata++;
 509                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 510                 len = SPRINTF((tmp, "%s %d %d %lu ",
 511                                p_type(type), algorithm, labels, t));
 512                 T(addstr(tmp, len, &buf, &buflen));
 513                 if (labels > (u_int)dn_count_labels(name))
 514                         goto formerr;
 515
 516                 /* Signature expiry. */
 517                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 518                 len = SPRINTF((tmp, "%s ", p_secstodate(t)));
 519                 T(addstr(tmp, len, &buf, &buflen));
 520
 521                 /* Time signed. */
 522                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 523                 len = SPRINTF((tmp, "%s ", p_secstodate(t)));
 524                 T(addstr(tmp, len, &buf, &buflen));
 525
 526                 /* Signature Footprint. */
 527                 footprint = ns_get16(rdata);  rdata += NS_INT16SZ;
 528                 len = SPRINTF((tmp, "%u ", footprint));
 529                 T(addstr(tmp, len, &buf, &buflen));
 530
 531                 /* Signer's name. */
 532                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 533
 534                 /* Signature. */
 535                 len = b64_ntop(rdata, edata - rdata,
 536                                base64_key, sizeof base64_key);
 537                 if (len > 15) {
 538                         T(addstr(" (", 2, &buf, &buflen));
 539                         leader = "\n\t\t";
 540                         spaced = 0;
 541                 } else
 542                         leader = " ";
 543                 if (len < 0)
 544                         goto formerr;
 545                 for (n = 0; n < len; n += 48) {
 546                         T(addstr(leader, strlen(leader), &buf, &buflen));
 547                         T(addstr(base64_key + n, MIN(len - n, 48),
 548                                  &buf, &buflen));
 549                 }
 550                 if (len > 15)
 551                         T(addstr(" )", 2, &buf, &buflen));
 552 #endif /* !_LIBC */
 553                 break;
 554             }
 555
 556         case ns_t_nxt: {
 557                 int n, c;
 558
 559                 /* Next domain name. */
 560                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 561
 562                 /* Type bit map. */
 563                 n = edata - rdata;
 564                 for (c = 0; c < n*8; c++)
 565                         if (NS_NXT_BIT_ISSET(c, rdata)) {
 566                                 len = SPRINTF((tmp, " %s", p_type(c)));
 567                                 T(addstr(tmp, len, &buf, &buflen));
 568                         }
 569                 break;
 570             }
 571
 572         case ns_t_cert: {
 573                 u_int c_type, key_tag, alg;
 574                 int n, siz;
 575                 char base64_cert[8192], *leader, tmp[40];
 576
 577                 c_type  = ns_get16(rdata); rdata += NS_INT16SZ;
 578                 key_tag = ns_get16(rdata); rdata += NS_INT16SZ;
 579                 alg = (u_int) *rdata++;
 580
 581                 len = SPRINTF((tmp, "%d %d %d ", c_type, key_tag, alg));
 582                 T(addstr(tmp, len, &buf, &buflen));
 583                 siz = (edata-rdata)*4/3 + 4; /* "+4" accounts for trailing \0 */
 584                 if (siz > sizeof(base64_cert) * 3/4) {
 585                         char *str = "record too long to print";
 586                         T(addstr(str, strlen(str), &buf, &buflen));
 587                 }
 588                 else {
 589                         len = b64_ntop(rdata, edata-rdata, base64_cert, siz);
 590
 591                         if (len < 0)
 592                                 goto formerr;
 593                         else if (len > 15) {
 594                                 T(addstr(" (", 2, &buf, &buflen));
 595                                 leader = "\n\t\t";
 596                                 spaced = 0;
 597                         }
 598                         else
 599                                 leader = " ";
 600
 601                         for (n = 0; n < len; n += 48) {
 602                                 T(addstr(leader, strlen(leader),
 603                                          &buf, &buflen));
 604                                 T(addstr(base64_cert + n, MIN(len - n, 48),
 605                                          &buf, &buflen));
 606                         }
 607                         if (len > 15)
 608                                 T(addstr(" )", 2, &buf, &buflen));
 609                 }
 610                 break;
 611             }
 612
 613         case ns_t_tsig: {
 614                 /* BEW - need to complete this */
 615                 int n;
 616
 617                 T(len = addname(msg, msglen, &rdata, origin, &buf, &buflen));
 618                 T(addstr(" ", 1, &buf, &buflen));
 619                 rdata += 8; /* time */
 620                 n = ns_get16(rdata); rdata += INT16SZ;
 621                 rdata += n; /* sig */
 622                 n = ns_get16(rdata); rdata += INT16SZ; /* original id */
 623                 sprintf(buf, "%d", ns_get16(rdata));
 624                 rdata += INT16SZ;
 625                 addlen(strlen(buf), &buf, &buflen);
 626                 break;
 627             }
 628
 629         case ns_t_a6: {
 630                 struct in6_addr a;
 631                 int pbyte, pbit;
 632
 633                 /* prefix length */
 634                 if (rdlen == 0U) goto formerr;
 635                 len = SPRINTF((tmp, "%d ", *rdata));
 636                 T(addstr(tmp, len, &buf, &buflen));
 637                 pbit = *rdata;
 638                 if (pbit > 128) goto formerr;
 639                 pbyte = (pbit & ~7) / 8;
 640                 rdata++;
 641
 642                 /* address suffix: provided only when prefix len != 128 */
 643                 if (pbit < 128) {
 644                         if (rdata + pbyte >= edata) goto formerr;
 645                         memset(&a, 0, sizeof(a));
 646                         memcpy(&a.s6_addr[pbyte], rdata, sizeof(a) - pbyte);
 647                         (void) inet_ntop(AF_INET6, &a, buf, buflen);
 648                         addlen(strlen(buf), &buf, &buflen);
 649                         rdata += sizeof(a) - pbyte;
 650                 }
 651
 652                 /* prefix name: provided only when prefix len > 0 */
 653                 if (pbit == 0)
 654                         break;
 655                 if (rdata >= edata) goto formerr;
 656                 T(addstr(" ", 1, &buf, &buflen));
 657                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 658
 659                 break;
 660             }
 661
 662         case ns_t_opt: {
 663                 len = SPRINTF((tmp, "%u bytes", class));
 664                 T(addstr(tmp, len, &buf, &buflen));
 665                 break;
 666             }
 667
 668         default:
 669                 snprintf (errbuf, sizeof (errbuf), "unknown RR type %d", type);
 670                 comment = errbuf;
 671                 goto hexify;
 672         }
 673         return (buf - obuf);
 674  formerr:
 675         comment = "RR format error";
 676  hexify: {
 677         int n, m;
 678         char *p;
 679
 680         len = SPRINTF((tmp, "\\#(\t\t; %s", comment));
 681         T(addstr(tmp, len, &buf, &buflen));
 682         while (rdata < edata) {
 683                 p = tmp;
 684                 p += SPRINTF((p, "\n\t"));
 685                 spaced = 0;
 686                 n = MIN(16, edata - rdata);
 687                 for (m = 0; m < n; m++)
 688                         p += SPRINTF((p, "%02x ", rdata[m]));
 689                 T(addstr(tmp, p - tmp, &buf, &buflen));
 690                 if (n < 16) {
 691                         T(addstr(")", 1, &buf, &buflen));
 692                         T(addtab(p - tmp + 1, 48, spaced, &buf, &buflen));
 693                 }
 694                 p = tmp;
 695                 p += SPRINTF((p, "; "));
 696                 for (m = 0; m < n; m++)
 697                         *p++ = (isascii(rdata[m]) && isprint(rdata[m]))
 698                                 ? rdata[m]
 699                                 : '.';
 700                 T(addstr(tmp, p - tmp, &buf, &buflen));
 701                 rdata += n;
 702         }
 703         return (buf - obuf);
 704     }
 705 }
 706
 707 /* Private. */
 708
 709 /*
 710  * size_t
 711  * prune_origin(name, origin)
 712  *      Find out if the name is at or under the current origin.
 713  * return:
 714  *      Number of characters in name before start of origin,
 715  *      or length of name if origin does not match.
 716  * notes:
 717  *      This function should share code with samedomain().
 718  */
 719 static size_t
 720 prune_origin(const char *name, const char *origin) {
 721         const char *oname = name;
 722
 723         while (*name != '\0') {
 724                 if (origin != NULL && ns_samename(name, origin) == 1)
 725                         return (name - oname - (name > oname));
 726                 while (*name != '\0') {
 727                         if (*name == '\\') {
 728                                 name++;
 729                                 /* XXX need to handle \nnn form. */
 730                                 if (*name == '\0')
 731                                         break;
 732                         } else if (*name == '.') {
 733                                 name++;
 734                                 break;
 735                         }
 736                         name++;
 737                 }
 738         }
 739         return (name - oname);
 740 }
 741
 742 /*
 743  * int
 744  * charstr(rdata, edata, buf, buflen)
 745  *      Format a <character-string> into the presentation buffer.
 746  * return:
 747  *      Number of rdata octets consumed
 748  *      0 for protocol format error
 749  *      -1 for output buffer error
 750  * side effects:
 751  *      buffer is advanced on success.
 752  */
 753 static int
 754 charstr(const u_char *rdata, const u_char *edata, char **buf, size_t *buflen) {
 755         const u_char *odata = rdata;
 756         size_t save_buflen = *buflen;
 757         char *save_buf = *buf;
 758
 759         if (addstr("\"", 1, buf, buflen) < 0)
 760                 goto enospc;
 761         if (rdata < edata) {
 762                 int n = *rdata;
 763
 764                 if (rdata + 1 + n <= edata) {
 765                         rdata++;
 766                         while (n-- > 0) {
 767                                 if (strchr("\n\"\\", *rdata) != NULL)
 768                                         if (addstr("\\", 1, buf, buflen) < 0)
 769                                                 goto enospc;
 770                                 if (addstr((const char *)rdata, 1,
 771                                            buf, buflen) < 0)
 772                                         goto enospc;
 773                                 rdata++;
 774                         }
 775                 }
 776         }
 777         if (addstr("\"", 1, buf, buflen) < 0)
 778                 goto enospc;
 779         return (rdata - odata);
 780  enospc:
 781         __set_errno (ENOSPC);
 782         *buf = save_buf;
 783         *buflen = save_buflen;
 784         return (-1);
 785 }
 786
 787 static int
 788 addname(const u_char *msg, size_t msglen,
 789         const u_char **pp, const char *origin,
 790         char **buf, size_t *buflen)
 791 {
 792         size_t newlen, save_buflen = *buflen;
 793         char *save_buf = *buf;
 794         int n;
 795
 796         n = dn_expand(msg, msg + msglen, *pp, *buf, *buflen);
 797         if (n < 0)
 798                 goto enospc;    /* Guess. */
 799         newlen = prune_origin(*buf, origin);
 800         if (newlen == 0) {
 801                 /* Use "@" instead of name. */
 802                 if (newlen + 2 > *buflen)
 803                         goto enospc;        /* No room for "@\0". */
 804                 (*buf)[newlen++] = '@';
 805                 (*buf)[newlen] = '\0';
 806         } else {
 807                 if (((origin == NULL || origin[0] == '\0') ||
 808                     (origin[0] != '.' && origin[1] != '\0' &&
 809                     (*buf)[newlen] == '\0')) && (*buf)[newlen - 1] != '.') {
 810                         /* No trailing dot. */
 811                         if (newlen + 2 > *buflen)
 812                                 goto enospc;    /* No room for ".\0". */
 813                         (*buf)[newlen++] = '.';
 814                         (*buf)[newlen] = '\0';
 815                 }
 816         }
 817         *pp += n;
 818         addlen(newlen, buf, buflen);
 819         **buf = '\0';
 820         return (newlen);
 821  enospc:
 822         __set_errno (ENOSPC);
 823         *buf = save_buf;
 824         *buflen = save_buflen;
 825         return (-1);
 826 }
 827
 828 static void
 829 addlen(size_t len, char **buf, size_t *buflen) {
 830         assert(len <= *buflen);
 831         *buf += len;
 832         *buflen -= len;
 833 }
 834
 835 static int
 836 addstr(const char *src, size_t len, char **buf, size_t *buflen) {
 837         if (len >= *buflen) {
 838                 __set_errno (ENOSPC);
 839                 return (-1);
 840         }
 841         memcpy(*buf, src, len);
 842         addlen(len, buf, buflen);
 843         **buf = '\0';
 844         return (0);
 845 }
 846
 847 static int
 848 addtab(size_t len, size_t target, int spaced, char **buf, size_t *buflen) {
 849         size_t save_buflen = *buflen;
 850         char *save_buf = *buf;
 851         int t;
 852
 853         if (spaced || len >= target - 1) {
 854                 T(addstr("  ", 2, buf, buflen));
 855                 spaced = 1;
 856         } else {
 857                 for (t = (target - len - 1) / 8; t >= 0; t--)
 858                         if (addstr("\t", 1, buf, buflen) < 0) {
 859                                 *buflen = save_buflen;
 860                                 *buf = save_buf;
 861                                 return (-1);
 862                         }
 863                 spaced = 0;
 864         }
 865         return (spaced);
 866 }